Packaging material and method

ABSTRACT

An improved packaging material may include a substrate which is normally susceptible to permeation by substances such as oil or grease. A colorant layer may be applied to the outer surface of the substrate. The colorant layer may be of a color chosen to closely resemble or to overpower the appearance of a stain on the substrate which would otherwise be caused by the substances. In this manner, the colorant layer serves to mask the stain which would otherwise be caused by substances permeating through the substrate. A second colorant layer may optionally be provided over the first colorant layer to provide a uniform background of a desired color. Graphics, e.g, text and/or images, may then be applied to the first or second colorant layer in a conventional manner.

FIELD OF THE INVENTION

The present invention relates generally to packaging material used toform packages for products and, more specifically, to packaging materialhaving the ability to mask stains caused by the product being packaged.

BACKGROUND OF THE INVENTION

Products, and in particular food products, are commonly packaged inpaperboard boxes or cartons. Examples of such paperboard boxes orcartons include cereal boxes, milk cartons, butter and margarine boxesand beer and soft drink secondary packaging (e.g., paperboard cartonsenclosing a plurality of beer or softdrink cans or bottles). Forexplanatory purposes, the simple term “cartons” may be used throughoutthis description to refer to the type of paperboard boxes or cartonsdescribed above.

The process of forming this type of carton typically begins by printinga continuous web of paperboard material with the particular graphicsdesired for the package in question. The paperboard material may, forexample, have a thickness of between about 0.001 and about 0.040 inch.Before printing, the paperboard material may, for example, be of a brownor grey color. Alternatively, the paperboard material may be bleached orcoated so as to exhibit a generally white color. A typical web ofpaperboard material may, for example, have a length of between about10,000 and about 30,000 feet and may be wound into a roll format.

To print a web of material, the web of material may be mounted on a reelat one end of a web printing machine. Such a web printing machinetypically includes various printing stations, each of the printingstations being adapted to apply a different pattern and color of ink tothe web. Each printing station may employ an ink application method suchas a gravure or a flexographic method, as is well-known in the webprinting industry. As can be appreciated, this type of printing machinewill typically have a number of active printing stations equal to thenumber of graphics colors to be applied to the web. A drying station mayalso be located after each of the printing stations such that each colorpattern will be dried before that portion of the web enters the nextprinting station.

The end of the web of material may then be threaded through the webprinting machine and thereafter rewound onto an output reel at theopposite end of the printing machine. In this manner, the entire web maybe fed through the printing machine. Within the printing machine, thegraphics for the desired package are repeatedly printed along the web.

After printing is completed, the printed web is removed from the outputreel of the printing machine and transferred to a cutting and scoringmachine. The cutting and scoring machine cuts the web into a pluralityof carton blanks, each of which is registered with the graphics printedin the printing machine. Examples of cutting and scoring machines aregenerally disclosed in U.S. Pat. No. 4,781,317 and U.S. Pat. No.5,757,930, both of which are hereby incorporated by reference for allthat is disclosed therein. Depending on the design of the particularcarton blank, the blank may also be folded or partially folded and gluedafter completion of the cutting and scoring operation.

The carton blanks may then be shipped to the product filling location.Here, the carton blanks are erected and the desired product inserted.Any necessary final gluing, depending on the type of carton, may also beaccomplished at this time. Examples of carton blanks and of cartonsformed therefrom are disclosed in U.S. Pat. No. 5,092,516 and U.S. Pat.No. 5,632,404, both of which are hereby incorporated by reference forall that is disclosed therein.

A problem arises when paperboard cartons are used to package productswhich contain fluids that are capable of permeating the paperboard.Examples of such problematic products include those which are oily orgreasy, e.g., products such as butter or margarine. Specifically, oil orgrease from such products can penetrate the paperboard of the carton andappear as a stain on the outside of the carton. Such staining detractsfrom the appearance of the carton and may interfere with the graphicsprinted thereon. One solution to this problem is to use a modifiedpaperboard material. Such modified paperboard materials are generallytreated with a chemical which makes the paperboard material impermeableto oil and grease. Although this type of material works well to preventoil and grease migration, it is relatively expensive.

Another solution to the problem of oil and grease migration is proposedin U.S. Pat. No. 4,521,492, which is hereby incorporated by referencefor all that is disclosed therein. This solution involves coating thepaperboard material with a non-leafing metallic ink and a highlypigmented white ink prior to printing graphics onto the paperboardmaterial. The use of metallic inks, however, is disadvantageous forseveral reasons. At the outset, metallic inks are relatively expensiveand their use, thus, prohibitively adds cost to the package. Metallicinks also have a detrimental effect on printability; specifically, it isdifficult to obtain good adhesion between a metallic ink layer and asubsequently applied ink layer. Finally, metallic inks are difficult toapply, often, for example, causing plugging of printing machine rollers.

Thus, it would be generally desirable to provide a solution to theproblem of grease and oil migration staining in cartons that overcomesthe problems associated with prior proposed solutions.

SUMMARY OF THE INVENTION

The present invention is generally directed to an improved packagingmaterial. The packaging material may include a substrate which isnormally susceptible to permeation by oil or grease. A non-whitenon-metallic colorant layer may be applied to the outer surface of thesubstrate. The specific color of the colorant layer may be chosen toclosely resemble or to overpower the appearance of a stain on thesubstrate caused by oil or grease permeating through the substrate. Inthis manner, the colorant layer serves to mask the stain and, thus, toprevent the stain from appearing on the finished package.

A second non-metallic colorant layer may be provided over the firstcolorant layer to provide a uniform background of a desired color, e.g.,white. Graphics, e.g, text and/or images, may then be applied to thesecond colorant layer in a conventional manner. Alternatively, thesecond colorant layer may be applied only in areas where no graphics areto be applied or may be applied in both areas where no graphics are tobe applied and in areas where graphics of light color and/or low opacityare to be applied. As a further alternative, the second colorant layermay be omitted entirely and the color of the first colorant layer may beused as the background color for the package.

It has been found that, in many cases, oil or grease cause agrey-colored stain on a substrate. Accordingly, a grey colored firstcolorant layer may be used to mask such a stain. In the case where thecolorant is an ink, such a grey colorant may be formed from a white inkhaving a black pigment mixed therein.

The colorant layers may be applied in any conventional manner. In thecase where the colorant is an ink, for example, the ink may be appliedin a conventional web printing machine. The first printing station ofthe web printing machine may be modified to apply a substantiallycontinuous layer of ink, rather than graphics. Where a second layer isalso to be provided, the second station of the printing machine may alsobe modified to apply a substantially continuous layer of ink. Theremaining stations in the printing machine may operate in a conventionalmanner.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a carton blank formed from a packagingmaterial having stain masking abilities.

FIG. 2 is a cross-sectional elevational view taken along the line 2-2 ofFIG. 1.

FIG. 3 is a cross-sectional view similar to that of FIG. 2, butillustrating an alternative embodiment.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-3, in general, illustrate a packaging material 10, 210 forpackaging grease or oil-containing substances. The packaging material10, 210 may include a substrate 90, 290 which is normally susceptible topermeation by oil or grease. The substrate may have a first surface 92,292 thereon. The packaging material 10, 210 may further include graphics64, 264 and at least one colorant layer 100, 300 located between thegraphics 64, 264 and the first surface 92, 292 of the substrate 90, 290.The at least one colorant layer 100, 300 may comprise a non-metallicnon-white colorant.

FIGS. 1-3, further illustrate, in general, a method of making apackaging material 10, 210 for packaging a grease or oil-containingproduct. The method may include providing a substrate 90, 290 which isnormally susceptible to permeation by oil or grease and applying atleast one layer 100, 300 of non-metallic non-white colorant to a firstsurface 92, 292 of the substrate 90, 290.

FIGS. 1-3, further illustrate, in general, a method of making apackaging material 10, 210 for packaging a grease or oil-containingproduct. The method may include providing a substrate 90, 290 which isnormally susceptible to permeation by oil or grease from the product andto staining thereby; applying a first layer 100, 300 of colorant to afirst surface 92, 292 of the substrate 90, 290 and choosing the color ofthe colorant based upon the color of the staining of the substrate 90,290 caused by the oil or grease from the product.

Having thus described the packaging material and method in general, theywill now be described in further detail.

FIG. 1 illustrates a carton blank 10. Carton blank 10 may be formedhaving a plurality of fold lines, such as the fold lines 12, 14, 16, 18,20, 22, 24, 26, 28, 30, 32 and 34 (such fold lines are also sometimesreferred to in the carton industry as “score lines”). These fold linesdefine end panels 40 and 42 and side panels 44, 46, 48, 50, 54, 56, 58and 60. The carton blank 10 may be shaped and configured such that itcan be erected, in a generally conventional manner, into a carton forcontaining a product. Specifically, to erect the carton blank 10 into acarton, the carton blank 10 may be folded about the fold lines 12, 14,16 and 18 and the end panels 40 and 42 glued to one another. A product,e.g., sticks of margarine or butter, may then be slid into the cartonthrough one of the open sides.

After the product has been inserted, the sides may be sealed.Specifically, the side panels 44 and 48 may be folded inwardly about thefold lines 20 and 24, respectively. The side panels 46 and 50 may thenbe folded inwardly about the fold lines 22 and 26, respectively, andglued to one another. In a similar manner, the side panels 54 and 58 maybe folded inwardly about the fold lines 28 and 32, respectively. Theside panels 56 and 60 may then be folded inwardly about the fold lines30 and 34, respectively, and glued to one another. In this manner, afully enclosed carton may be formed for housing a product to bemarketed.

Referring again to FIG. 1, the carton blank 10 may include graphics 64applied thereto. The graphics 64 may include text 70 and/or images 80.Such graphics may serve to identify the product contained within thecarton to a consumer or potential consumer. The graphics 64 also mayserve to produce an appearance for the overall package which isaesthetically pleasing to a consumer or potential consumer. It is notedthat the graphics 64 are illustrated in FIG. 2 on only one panel 62 ofthe carton blank 10 for purposes of illustrative clarity. It is to beunderstood, however, that, in actual use, several or all of the panelsof the carton blank 10 may include graphics in a conventional manner.

FIG. 2 is a partial cross-sectional view of the carton blank 10, takenalong the line 2-2 in FIG. 1. Referring to FIG. 2, the carton blank 10may include a paperboard substrate having an outer surface 92 and aninner surface 94. Paperboard substrate 90 may, for example, be of thetype known in the industry as a “solid bleached sulfite” or “SBS”paperboard. The entire composition of this type of substrate, includingthe outer surface 92, is of a white color. Paperboard substrate 90 may,for example, have a thickness of about 0.012 inch. As can beappreciated, the inner surface 94 of the substrate 90 also forms thelower surface of the carton blank 10 and, thus, will form the innersurface of a carton erected from the carton blank 10. Accordingly, theinner surface 94 is the surface of the erected carton that contacts theproduct to be packaged within the carton. This contact may either bedirect or via supplemental product packaging, e.g., wax paper, in whichthe actual product may be packaged.

As discussed previously, a problem arises when paperboard cartons areused to package products which contain fluids that are capable ofpermeating the paperboard. Examples of such problematic products includethose which are oily or greasy, e.g., products such as butter ormargarine. Specifically, oil or grease from such products can penetratethe paperboard of the carton and appear as a stain on the outside of thecarton. Such staining detracts from the appearance of the carton and mayinterfere with the graphics appearing thereon.

The carton blank 10 overcomes this problem in a manner as will now bediscussed in detail. It has been discovered that the staining describedabove appears as a darkened area on the outer surface 92 of thesubstrate 90. It has further been discovered that the appearance of suchstaining can be masked by applying to the outer surface 92 a layer ofnon-metallic non-white colorant having substantially the same color asthe stain.

It has been found, for example, that oil and grease stains on solidbleached sulfite paperboard appear having a grey color. Accordingly,this type of stain can be masked by applying a layer of non-metallicgrey colorant between the graphics 64 and the substrate 90 in a manneras will be described in further detail below. The layer of greycolorant, thus, serves to mask the appearance of grease or oil stainsand thus, prevent such stains from interfering with the appearance of acarton formed from the carton blank 10.

It is noted that the term “colorant” is used herein to denote anysubstance designed to impart color to a surface. The term colorant,thus, is intended to include, for example, inks, paints, dyes andstains.

It is further noted that the term “non-metallic” colorant is used hereinto mean a colorant that does not contain any metallic elements in morethan negligible/trace quantities (for example, those quantities thatwould incidentally be present as a result of the manufacturing processesto be employed). In other words, the non-metallic colorant describedherein will not include any metallic elements aside from minute, traceamounts that would be considered inconsequential. As previouslydescribed, the use of metallic colorants, e.g., metallic inks, isdisadvantageous in that such metallic colorants, for example, arerelatively expensive, have a detrimental effect on printability and aredifficult to apply. Accordingly, the use of a non-metallic colorant ispreferred.

In the carton industry, inks represent the most commonly used colorants.Typical inks generally include a carrier, a binder and a pigment. Thecarrier serves to carry the other components and is intended toevaporate after the ink is applied, thus causing the ink to dry.Carriers may be either water or solvent based. Some inks, knowngenerally in the industry as “energy curable inks” utilize a reactivediluent instead of a carrier. Rather than evaporating, as does aconventional carrier, a reactive diluent polymerizes and becomes part ofthe cured ink film after the energy curable ink is exposed to an energysource, e.g., ultraviolet light or electron beam radiation.

The ink pigment serves to impart the desired color to the ink. A typicalpigment used in white ink, for example, is titanium dioxide. Typicalpigments used in black ink include carbon and iron oxide. Colors otherthan white and black can, of course, be formulated by using a differentpigment or a combination of pigments. The binder in an ink serves toadhere the pigment to the substrate onto which the ink is printed.

Referring again to FIG. 2, a first layer of non-metallic non-whitecolorant 100 may be applied directly to the paperboard substrate 90. Thefirst layer 100 may, for example, be a grey colorant layer and mayextend over the entire surface area of the carton blank 10. A secondlayer of non-metallic colorant 110 may be applied directly on the layer100 as illustrated in FIG. 2. Second layer 110 may also extend over theentire surface area of the carton blank 10. Finally, the desiredgraphics 64 may be applied directly on the second layer 110. It is notedthat FIG. 2 is not to scale and that, for purposes of illustration, thethickness of the colorant layers 100, 110 and the graphics 64 has beenexaggerated relative to the thickness of the substrate 90. As describedin further detail herein, in actuality, the thickness of the colorantlayers 100, 110 and the graphics 64 is much less than the thickness ofthe substrate 90.

First colorant layer 100 may, for example, have a thickness of betweenabout 1 and about 8 microns and, more preferably, between about 2 andabout 4 microns. Most preferably, the first colorant layer 100 may havea thickness of about 3 microns. First colorant layer 100 may, forexample, be formed having a grey color in order to mask a grey coloredstain, as described above.

First colorant layer 100 may, for example, be formed from a grey inkwhich is formed by mixing a black ink and a white ink. The black ink,for example, may include a conventional water based carrier, aconventional binder, and a carbon pigment. The black ink may, forexample, be of the type produced by Progressive Ink Company, LLC of 4150Carr Lane Court, St. Louis, Mo. 63119 and identified as formula numberWBJ9004.

The white ink, for example, may include a conventional water basedcarrier, a conventional binder, and a titanium dioxide pigment. Thewhite ink may, for example, be of the type produced by Progressive InkCompany, LLC of 4150 Carr Lane Court, St. Louis, Mo. 63119 andidentified as formula number WBJ1000.

To produce the exemplary grey ink described above, the black and whiteinks described above may be mixed together. Specifically, the black inkmay have a concentration of between about 0.01 percent and about 15percent by weight of the total black ink/white ink mixture. Morepreferably, the black ink may be introduced at a concentration ofbetween about 1 percent and about 10 percent by weight of the totalblack ink/white ink mixture. Most preferably, the black ink may beintroduced at a concentration of about 2 percent by weight of the totalblack ink/white ink mixture.

It is noted that, as used herein, the term “non-white colorant” means acolorant having any non-white color element included therein. The greyink described above, for example, is one example of a “non-whitecolorant”. Although this ink includes a white pigment (e.g., titaniumdioxide), it is considered to be a “non-white colorant” because it alsoincludes a non-white (i.e., black in this case) pigment. In a similarmanner, an ink that includes a non white color pigment (e.g., blue orgreen) and no white pigment would also be considered to be a “non-whitecolorant” for purposes of this discussion.

The grey ink described above, when used as the first colorant layer 100,serves to mask oil and/or grease stains caused by product packagedwithin a carton and to prevent such stains from appearing on the outersurface of the carton. As described above, it has been discovered thatmost oil and grease stains are visible through graphics applied tocartons because of the darkening created from the stains. Rather thanacting as a barrier, the colorant layer 100 serves to mask the stain byeither closely resembling the stain color or by overwhelming the stainwith colorant of a darker color. The colorant layer 100, thus, serves tomask or hide the stain rather than to block or prevent it. The use of anon-metallic grey ink for the colorant layer 100 to mask stains, asdescribed herein, is advantageous due to ease of production in producinga grey-colored ink and the absence of the need for any expensive fillersor metal based powders.

It is noted that the specific configuration of the carton blank 10, asillustrated in FIG. 1, is described herein for exemplary purposes only.The stain masking attributes of the present invention may, of course, beused in conjunction with any package configuration.

The first colorant layer 100 may, alternatively, be formed from colorantwhich is entirely black. Although such a black colorant layer has beenfound to mask stains well, it may show through the second colorant layer110. When, for example, a white second colorant layer 110 is used, theuse of black first colorant layer 100 may cause the second colorantlayer to appear grey, rather than white. This grey appearance may beundesirable in some situations. The use of a grey colorant, rather thana black colorant for the first colorant layer 100 overcomes thispotential problem while still providing adequate stain masking ability.

Referring to FIGS. 1 and 2, it can be appreciated that the secondcolorant layer 110 will be visible in areas where no graphics 64 havebeen applied. Accordingly, the second colorant layer 110 serves toprovide a uniform background color for the carton blank 10. Secondcolorant layer 110 may have a thickness of between about 1 and about 8microns and most preferably about 4 microns.

Second colorant layer 110 may, for example, be formed from a white inkcomprising, e.g., a conventional water based carrier, a conventionalbinder, and a titanium dioxide pigment. The white ink may, for example,be of the type produced by Progressive Ink Company, LLC of 4150 CarrLane Court, St. Louis, Mo. 63119 and identified as formula number 1N002.Although the white colorant described above has been found to work well,a differently colored colorant may be substituted in order to provide abackground having any desired color.

As an alternative to applying the second colorant layer 110 over theentire surface of the first colorant layer 100, the second colorantlayer 110 may be omitted in areas where graphics having high opacity areto be applied.

Further, if a grey (the color of the colorant layer 100) background isdesired, the second colorant layer 110 may be omitted entirely and thegraphics 64 applied directly on the grey colorant layer 100.

The carton blank 10 may, for example, be formed in a conventionalcarton-making process. Such a conventional process may begin with a webprinting machine which applies printing inks to a moving web ofsubstrate material. Specifically, a continuos web of paperboard materialmay be provided having a thickness and composition identical to that ofthe carton blank substrate layer 90 described above. The web of materialmay be mounted on a reel, in a conventional manner, and rotatablymounted near one end of a conventional web printing machine. Such webprinting machines typically include various printing stations, each ofthe printing stations being adapted to apply a different pattern andcolor to the web. Each printing station may employ an application methodsuch as lithographic, roto-gravure or flexographic printing, as iswell-known in the industry. As can be appreciated, such a conventionalprinting machine will typically have a number of active printingstations equal to the number of graphics colors to be applied to theweb. A drying station may also be located after each of the printingstations such that each color pattern will be dried before that portionof the web enters the next printing station.

The end of the web may be threaded through the web printing machine andthen rewound onto an output reel at the opposite end of the printingmachine. The web printing machine may be of the type conventionally usedto print graphics onto a moving web of material, except that the firsttwo printing stations of the machine may be modified as follows.

Rather than printing graphics, as in a conventional printing station,the first printing station may be configured to apply a continuous layerover substantially the entire upper surface of the web. This layer willbecome the first layer 100, as previously described with respect to FIG.2. Accordingly, the first printing station may be provided, for example,with grey or black ink as previously described in conjunction with thefirst layer 100.

In some cases, multiple carton blank patterns are printed across thewidth of a web, with spaces existing between adjacent patterns. In thiscase, in order to reduce ink waste, the first printing station may,alternatively, be configured to print the first layer 100 only in theareas where the carton blank patterns exist and not in the spacestherebetween. Since the first ink layer 100 will be omitted only inthese relatively small spaces, the first layer 100 will still extendover substantially the entire upper surface of the web. For purposes ofthis description, such substantially complete coverage is considered toconstitute a continuous layer of colorant.

In a similar manner to the first printing station, the second printingstation may also be configured to apply a continuous layer oversubstantially the entire upper surface of the web. This layer willbecome the second layer 110, as previously described. Accordingly, thesecond printing station may, for example, be provided with white ink aspreviously described in conjunction with the second layer 110.Alternatively, as described above, in the case where multiple cartonblank patterns are printed across the width of a web, the secondprinting station may be configured to print the continuous layer only inthe areas where the carton blank patterns exist and not in the spacesexisting therebetween. As described above, in some cases, it may bedesired to omit the second layer 110 (and print the graphics directly onthe first layer 100). In this situation, the second printing station maybe omitted from the printing machine.

After the first and second (if used) printing stations, a third printingstation may be provided in order to print a first color of graphics ontothe second layer 110 (or directly onto the first layer 100 if the secondlayer 110 is not used). A fourth printing station may be provided inorder to print a second color of graphics onto the second layer 110 (ordirectly onto the first layer 100 if the second layer 110 is not used),and so on until the desired number of graphics colors have been applied.

At the output of the printing machine, the web may be rewound onto anoutput reel in a conventional manner. After the web has been printed itmay be removed from the output reel of the printing machine andtransferred to a conventional cutting and scoring machine. There, theweb may be transformed in a conventional manner into a plurality ofcarton blanks, such as the carton blank 10, described above.

Accordingly, a packaging material having stain masking abilities hasbeen disclosed that does not require the use of expensive andproblematic metallic inks.

It is noted that a specific manufacturing process for the carton blank10 has been described above for exemplary purposes only. In practice,the steps described above could be performed in a different order or adifferent process entirely could be used to form the carton blank 10,having the various colorant layers and graphics as described.

FIG. 3 is similar to FIG. 2, but illustrates an alternative embodimentof a carton blank having stain-masking ability. FIG. 3 illustrates acarton blank 210 which may be substantially identical to the cartonblank 10 previously described except for the colorant layers as will nowbe described in detail. With reference to FIG. 3, carton blank 210 mayinclude a paperboard substrate 290 having an outer surface 292 and aninner surface 294. Paperboard substrate 290 may, for example, besubstantially identical to the paperboard substrate 90 previouslydescribed with respect to FIG. 2.

Referring again to FIG. 3, a layer of non-metallic non-white colorant300 may be applied directly on the outer surface 292 of the paperboardsubstrate 290. The colorant layer 300 may be identical to the colorantlayer 100 previously described with respect to FIGS. 1 and 2.

Graphics 264, including text 270 and/or images 280, may be applieddirectly on the colorant layer 300. The embodiment of FIG. 3 differsfrom that of FIG. 2 in that a background colorant 350 may be applieddirectly on the first colorant layer 300 in areas where no graphics havebeen applied. In this manner, the background colorant 350 gives thevisual impression of a uniform background layer. Applying the colorant350 only in the areas where no graphics have been applied, however,requires the use of less colorant, e.g., ink, than does a continuouslyapplied background colorant layer, such as the layer 110, FIG. 2, sincethe colorant 350 need not be applied in the areas where graphics exist.It is noted that, in a similar manner to FIG. 2, FIG. 3 is not to scaleand, for purposes of illustration, the thickness of the colorant layer300 and the graphics 264 has been exaggerated relative to the thicknessof the substrate 290. As described in further detail herein, inactuality, the thickness of the colorant layer 300 and the graphics 264is much less than the thickness of the substrate 290.

The colorant 350 may have a thickness of between about 1 and about 8microns and, most preferably, about 4 microns. The colorant 350 may beof any color desired for the background of the particular package inquestion. Colorant 350 may, for example, be formed from a white inkcomprising, e.g., a conventional water based carrier, a conventionalbinder, and a titanium dioxide pigment. The white ink may, for example,be of the type produced by Progressive Ink Company, LLC of 4150 CarrLane Court, St. Louis, Mo. 63119 and identified as formula number 1N002.

The carton blank 210 may, for example, be formed in a manner similar tothat previously described with respect to the carton blank 10. Whenprinting the web for the carton blank 210, however, only the firstprinting station need be configured to apply a layer over substantiallythe entire upper surface of the web. This layer will become the layer300, as previously described. Accordingly, the first printing stationmay, for example, be provided with grey or black ink as previouslydescribed in conjunction with the colorant layer 100.

Another printing station in the printing machine may be configured toprint the desired pattern for the background colorant 350, FIG. 3. Aspreviously discussed, this pattern may correspond to areas wheregraphics are not printed. Accordingly, this printing station may beprovided, for example, with ink of the color desired for the backgroundof the carton.

Further printing stations may be provided in order to print the graphics264, as desired, in a conventional manner. After printing, the web maybe transformed into a plurality of carton blanks, in a manner asgenerally described with respect to the embodiment of FIG. 2.

It is noted that a specific manufacturing process for the carton blank210 has been described above for illustration purposes only. Inpractice, the steps described above could be performed in a differentorder or a different process entirely could be used to form the variousgraphics and colorant layers.

It is also noted that, although the foregoing description is directed tooil or grease staining, the stain masking concepts disclosed hereincould be equally applied to any other type of staining, e.g., stainingcaused by predominantly water based substances such as fruit juice, solong as the color of the first colorant layer is chosen to closelyresemble the color of the stain induced by the substance.

It is further noted that, although the foregoing description is directedto a paperboard substrate, the stain masking attributes described hereinare equally applicable to any other type of substrate which is permeableto oil, grease or other types of substances and, thus, subject toundesirable staining.

While illustrative and presently preferred embodiments of the inventionhave been described in detail herein, it is to be understood that theinventive concepts may be otherwise variously embodied and employed andthat the appended claims are intended to be construed to include suchvariations except insofar as limited by the prior art.

1. A packaging material for packaging grease or oil-containingsubstances, said packaging material comprising: (a) a substrate which issusceptible to permeation by oil or grease, said substrate having afirst surface thereon; (b) graphics; (c) at least one colorant layerlocated between said graphics and said first surface of said substrate;and (d) wherein said at least one colorant layer comprises anon-metallic non-white colorant.
 2. The packaging material of claim 1wherein said non-metallic non-white colorant is an ink.
 3. The packagingmaterial of claim 2 wherein said ink comprises a white pigment and ablack pigment.
 4. The packaging material of claim 2 wherein said ink isa grey ink.
 5. The packaging material of claim 1, wherein: at least aportion of said graphics is directly adjacent a portion of said at leastone colorant layer; and a background colorant is directly adjacent saidat least one colorant layer in areas where said at least a portion ofsaid graphics does not exist.
 6. The packaging material of claim 1 andfurther including a second colorant layer directly adjacent said atleast one colorant layer.
 7. The packaging material of claim 6 whereinsaid second colorant layer is a layer of white ink.
 8. The packagingmaterial of claim 6, wherein at least a portion of said graphics isdirectly adjacent at least a portion of said second colorant layer. 9.The packaging material of claim 1 wherein said packaging materialcomprises a carton blank.
 10. The packaging material of claim 1 whereinsaid packaging material comprises a web of packaging material.
 11. Thepackaging material of claim 1 wherein said at least one colorant layermasks the appearance of grease or oil stains on said packaging materialwhich stains are the result of grease or oil permeating said substratefrom the surface thereof opposite said first surface.
 12. A method ofmaking a packaging material for packaging a grease or oil-containingproduct, said method comprising: providing a substrate which issusceptible to permeation by oil or grease; and applying at least onelayer of non-metallic non-white colorant to a first surface of saidsubstrate.
 13. The method of claim 12 wherein said non-metallicnon-white colorant is an ink.
 14. The method of claim 13 wherein saidink is a grey ink.
 15. The method of claim 13 wherein said ink comprisesa white pigment and a black pigment.
 16. The method of claim 12 andfurther including applying graphics directly to at least a portion ofsaid at least one layer of said non-metallic non-white colorant.
 17. Themethod of claim 12 and further including; applying graphics directly toa portion of said at least one layer of non-metallic non-white colorant;and applying a second colorant layer directly to said at least one layerof non-metallic non-white colorant in areas where said graphics are notpresent.
 18. The method of claim 12 and further including applying asecond layer of colorant directly on said at least one layer ofnon-metallic non-white colorant.
 19. The method of claim 18 wherein saidsecond layer of colorant is a white ink.
 20. The method of claim 18 andfurther including applying graphics directly to at least a portion ofsaid second layer of colorant.
 21. The method of claim 12 and furthercomprising masking the appearance of grease or oil stains on saidpackage with said at least one layer of non-metallic nonwhite colorant,which stains are the result of grease or oil permeating said substratefrom said product.
 22. A method of making a packaging material forpackaging a grease or oil-containing product, said method comprising:providing a substrate which is susceptible to permeation by oil orgrease from said product and to staining thereby; applying a first layerof colorant to a first surface of said substrate; choosing the color ofsaid colorant based upon the color of said staining of said substratecaused by said oil or grease from said product.
 23. The method of claim22 wherein said first layer of colorant is a non-metallic non-whitecolorant.
 24. The method of claim 23 wherein said nonmetallic non-whitecolorant is an ink.
 25. The method of claim 22 and further includingapplying graphics directly to at least a portion of said first layer ofcolorant.
 26. The method of claim 22 and further including: applyinggraphics directly to a portion of said first layer of colorant; andapplying a second layer of colorant directly to said first layer ofcolorant in areas where said graphics are not present.
 27. The method ofclaim 22 and further including applying a second layer of colorantdirectly to said first layer of colorant.
 28. The method of claim 27 andfurther including applying graphics directly to at least a portion ofsaid second layer of colorant.
 29. A carton erected from the packagingmaterial of claim 1 and in combination with the grease or oil-containingsubstance, wherein the grease or oil-containing substance is enclosed bythe carton.
 30. The packaging material according to claim 1 and furtherincluding a second colorant layer covering at least a portion of said atleast one colorant layer such that said portion of said at least onecolorant layer is located between said second colorant layer and saidfirst surface of said substrate.
 31. The packaging material according toclaim 30 wherein said second colorant layer is visible where saidgraphics has not been applied and serves to provide a uniform backgroundcolor for a carton erected from said carton blank.
 32. The packagingmaterial according to claim 30 wherein said graphics covers at least aportion of said at least one colorant layer that is not covered by saidsecond colorant layer.
 33. The packaging material according to claim 32wherein said graphics is directly adjacent said second colorant layer,said graphics is directly adjacent said at least one colorant layer, andsaid second colorant layer is directly adjacent said at least onecolorant layer.
 34. A carton erected from the packaging material ofclaim 33 and in combination with the grease or oil-containing substance,wherein the grease or oil-containing substance is enclosed by thecarton.
 35. The method of claim 17 and further including forming a blankfrom the packaging material, wherein the blank is for being erected intoa carton.
 36. The method of claim 26 and further including forming ablank from the packaging material, wherein the blank is for beingerected into a carton.